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/* |
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* jQuery appear plugin |
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* |
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* Copyright (c) 2012 Andrey Sidorov |
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* licensed under MIT license. |
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* |
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* https://github.com/morr/jquery.appear/ |
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* |
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* Version: 0.3.3 |
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*/ |
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(function ($) { |
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var selectors = []; |
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|
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var check_binded = false; |
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var check_lock = false; |
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var defaults = { |
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interval : 250, |
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force_process: false |
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} |
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var $window = $(window); |
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|
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var $prior_appeared; |
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|
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function process() { |
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check_lock = false; |
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for (var index = 0; index < selectors.length; index++) { |
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var $appeared = $(selectors[index]).filter(function () { |
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return $(this).is(':appeared'); |
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}); |
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|
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$appeared.trigger('appear', [$appeared]); |
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|
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if ($prior_appeared) { |
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var $disappeared = $prior_appeared.not($appeared); |
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$disappeared.trigger('disappear', [$disappeared]); |
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} |
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$prior_appeared = $appeared; |
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} |
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} |
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|
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// "appeared" custom filter |
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$.expr[':']['appeared'] = function (element) { |
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var $element = $(element); |
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if (!$element.is(':visible')) { |
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return false; |
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} |
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|
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var window_left = $window.scrollLeft(); |
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var window_top = $window.scrollTop(); |
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var offset = $element.offset(); |
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var left = offset.left; |
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var top = offset.top; |
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|
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if (top + $element.height() >= window_top && |
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top - ($element.data('appear-top-offset') || 0) <= window_top + $window.height() && |
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left + $element.width() >= window_left && |
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left - ($element.data('appear-left-offset') || 0) <= window_left + $window.width()) { |
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return true; |
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} else { |
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return false; |
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} |
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} |
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|
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$.fn.extend({ |
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// watching for element's appearance in browser viewport |
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appear: function (options) { |
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var opts = $.extend({}, defaults, options || {}); |
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var selector = this.selector || this; |
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if (!check_binded) { |
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var on_check = function () { |
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if (check_lock) { |
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return; |
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} |
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check_lock = true; |
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|
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setTimeout(process, opts.interval); |
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}; |
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|
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$(window).scroll(on_check).resize(on_check); |
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check_binded = true; |
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} |
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|
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if (opts.force_process) { |
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setTimeout(process, opts.interval); |
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} |
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selectors.push(selector); |
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return $(selector); |
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} |
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}); |
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|
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$.extend({ |
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// force elements's appearance check |
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force_appear: function () { |
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if (check_binded) { |
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process(); |
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return true; |
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} |
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; |
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return false; |
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} |
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}); |
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})(jQuery); |
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|
